ANKARA (Reuters) - Turkish authorities on Wednesday detained 27 police officers in eight provinces across the country, the state-run Anadolu news agency said, part of the widening crackdown following a failed coup attempt in July.

The detentions, centered in the southern province of Adana, aimed to root out followers of the U.S.-based Muslim cleric Fethullah Gulen, whom Ankara accuses of orchestrating the putsch, and included three police chiefs, Anadolu reported.

Turkish authorities have detained, sacked or dismissed tens of thousands of people from the police, military, public service, judiciary, and elsewhere since the abortive coup over suspected ties to Gulen’s network.

Gulen, who has lived in self-imposed exile in Pennsylvania since 1999, has denied the charge and condemned the coup.

Rights groups and some of Turkey’s Western allies fear President Tayyip Erdogan is using the coup as a pretext to stifle dissent, but he says the moves are necessary to protect democracy and root out Gulen supporters.

Erdogan declared emergency rule after the failed coup, enabling the government to bypass parliament in enacting new laws and limit or suspend rights and freedoms when deemed necessary.

Turks will vote on April 16 on replacing the parliamentary system with the stronger presidency long sought by Erdogan. The referendum will be held under a state of emergency imposed after an attempted coup last July.

Turkey, a NATO member, has been hit by a series of bombings and shootings in the past year in addition to the coup, in which soldiers commandeered tanks and fighter jets in a bid to seize power, killing at least 240 people.